Excipient-API interactions in dry powder inhalers

  • Shireesh Apte


There remains a paucity of predictive models to evaluate excipient or excipient mixture suitability for dry powder inhalers because a large number of interdependent variables affect both formulation and inhaler performance. The problem is compounded by empirical studies that are performed under different experimental conditions which make data comparison difficult. An easily calculable molecular parameter - the Parachor relates structural constants to surface tension. When applied in conjunction with results obtained from inverse gas chromatography, the Parachor can be used to calculate adhesive and cohesive surface energies between excipients and active pharmaceutical ingredients. Values calculated from the Parachor are consistent with qualitative hypotheses and agree reasonably well with published quantitative results. The ability to both achieve and predict the free particle fraction from Parachor derived surface energy data represents a new paradigm worthy of further perusal.

Author Biography

Shireesh Apte
Scientist, Process Development, Alcon Research, Fort Worth, Texas Expert committe on macromolecular excipients, USP. Shireesh.P.Apte, Ph.D Work: (817) 551 4901 Home: (817) 453 1898 Cell: (817) 689 6086 Senior Scientist III Alcon Research, Fort Worth, TX Experience: June 98 To date Senior Scientist III, Product Research and Support, Alcon Research Ltd. , Fort Worth, TX Improved sterile manufacturing processes: Particulate elimination from an antibiotic solution, PET enhancement of an antifungal suspension, decreased filtration time for a predominantly non-aqueous antibiotic solution. Most process improvements incorporated into MBRs. June 97 June 98 Lead Scientist, Parenteral Development, Ohmeda Pharmaceutical Products Division, Murray Hill, NJ Developed and scaled up (2000 kg) a process for manufacture of Midazolam hydrochloride injection that involved predissolution of the base in benzyl alcohol prior to addition to acidified water in the reactor. The process resulted in at least an order of magnitude improvement in dissolution time. ANDA approved March 2000. Validation batches manufactured at Mova Pharmaceuticals, Caguas, Puerto Rico. Inventions 1. Patent project # 97A620, Propofol aqueous injectable solution. Propofol is dissolved in water containing hydroxy-propyl-?-cyclodextrin and human serum albumin , filed 12-16-1997 2. Patent project # 97A611, Process to reduce dissolution time of hydrophobic drugs in aqueous solvents, filed 8-28-1999 May 93 April 97 Research Scientist, Formulation and Process development, Pharmacia and Upjohn, Oncology div. Albuquerque, NM. 1. Formulated investigational and conventional anti-neoplastic parenteral drug products including liposomal, sustained release and protein dosage forms, wrote batch records, developed analytical methods, lyophilization cycles, scale up, compatibility and stability monitoring. Have worked in class 100 environments and have hands on knowledge with all aspects of aseptic manufacturing including CGMPs and GLPs. 2. Formulated a light activated drug; Tin Ethyl Purpurin (SnEt2) as a lyophilized lipid complex for I.V injection. Currently in Phase III clinical trials for Age Related Macular Degeneration (ARMD) being jointly developed by P & U and Miravant medical technologies, Santa Barbara, CA. 3. Formulated a neuron specific calcium channel blocker, SNX-111; a 25 mer peptide cone shell neurotoxin for treatment of chronic intractable pain for Neurex Corporation (Now Elan Corporation, PLC), as a lyophilized powder. NDA approved for Ziconotide?, July 2000. 4. Formulated a 29 mer peptide; Thymosin ?-1; as a lyophilized powder for SciClone Pharmaceutical International Ltd, San Mateo, CA. Approved for treatment of Hepatitis B as Zadaxin?. 5. Formulated a mixed backbone oligonucleotide (GEM?-231) for Hybridon, Milford, MA, as a Protein Kinase A inhibitor. The lyophilized powder is in Phase II trials for solid tumors. 6. Formulated a lyophillized generic equivalent of Mutamycin? (Mitomycin for injection), AADA approved december 1996. Inventions 1. U.S.Patent No. 6608050, issued 8/19/2003, Pharmacia and Upjohn, Lyophilizate of lipid complex of water insoluble porphyrins. Fall 94 Spring 96 Guest speaker, school of pharmacy, University of New Mexico. Taught selected topics in physical pharmacy. Jan 92 May 92 Co-op, McNeil Consumer Products Ltd., Drug delivery research. Formulated a bilayer tablet with an immediate release terfenadine component and a sustained release acetaminophen and terfenadine component. July 89 Oct 89 Summer Intern, Quad Pharmaceuticals, Indianapolis, IN Jan 88 July 88 Sales Representative, Elder Pharmaceuticals Pvt. Ltd., Bombay, India. May 86 Aug 86 Summer Intern, German Remedies Ltd., Bombay. Evaluated characteristics of several granulations of a dipyridamole (Persantin) formulation for optimum compressibility, dissolution and stability. Affiliations 1. Member, Unites States Pharmacopoeia, Excipients2 Expert Chair Committee, 2005-2010. 2. Founder and partner, Chemologic LLC, Mansfield, Texas. 3. Professional Home Inspector, Licence No. 5839, Texas, USA 4. Recreational Soccer Coach for U9 boys for the Mansfield Soccer Association. 5. Licenced Pharmacist in the state of Maharashtra, India. Publications: 1. Antimicrobial drugs that target human not microbial genotypes or phenotypes: a paradigm change in human evolutionary response to pathogen selection pressure. S.P.Apte, P.P. Apte, Med. Hypotheses. Doi: 10.1016/j.mehy.2006.01.043. 2. The polymerization of melanin: a poorly understood phenomenon with egregious biological implications. R. Sarangarajan. S.P.Apte, Melanoma Res. 2006; 16: 3-10. 3. Hypoxia targeted bioreductive tyrosine kinase inhibitors with glutathione depleting function. S.O.Ugwu, S.P.Apte, R. Sarangarajan. Anticancer drugs, 2005; 17(1): 21-24. 4. Rethinking drug specificity as a desirable objective in the context of interconnected signaling pathways. R. Sarangarajan, S.P.Apte. Pharmaceutical Discovery, August 2005. 5. Melanization and Phagocytosis: Implications for age related macular degeneration. R. Sarangarajan, S.P. Apte. Molecular Vision. 2005; 11: 482-490. 6. Melanin aggregation and polymerization: implications in age related macular degeneration. R. Sarangarajan, S.P.Apte. Ophthalmic Research 2005; 37: 136-141. 7. Emerging excipients demand new regulations: new mechanisms, guidelines and procedures are needed to regulate the functionality of new and emerging excipients. S.P.Apte, A.Katdare. Pharmaceutical Technolgy. Jan 2005. 8. Ocular melanogenesis: The role of antioxidants. R.Sarangarajan, S.P.Apte, Ophthalmic Research 2004; 36: 303-311. 9. The effect of buffers on protein conformational stability. S.O.Ugwu, S.P.Apte, Pharmaceutical Technology, March 2004: 86-113. 10. A simple method for determination of surface volume mean diameters of oil in water submicron emulsions. S.P.Apte, S.O.Ugwu, Die Pharmazie 2004; 59: 530-533. 11. Use of sodium chloride to facilitate reduction of particle size of dexamethasone during ball milling. S.P.Apte, et.al., Drug Development and Industrial Pharmacy, 29(3), 367-73, 2003. 12. A review and classification of emerging excipients in parenteral medications. S.P.Apte and S.O.Ugwu. J. Pharmaceutical Technology, March 2003 and Pharmaceutical Technology Europe, December 2003, January 2004. 13. Systematic screening of antioxidants for maximum protection against oxidation: An oxygen polarograph study. S.P.Apte and S.O.Ugwu. PDA J. Pharm. Sci. and Tech., 53(5), 252-9, (1999) 14. Surfactant interfacial configuration in a concentrated parenteral fluorocarbon emulsion. S.P.Apte and S.J.Turco. J. Dispersion Sci. and Tech., 14(5), (1993) 15. A novel method to map size distributions of parenteral fluorocarbon emulsions. S.P.Apte and S.J.Turco. J. Parenteral Sci. and Tech., 46(6), (1992) 16. Influence of manufacturing parameters on the formation and growth on autoclaving of a 40% v/v Bis-perfluorobutyl ethene parenteral emulsion. S.P.Apte and S.J.Turco. J. Parenteral Sci. and Tech., 46(1), (1992). Selected Presentations: 1. Emerging excipients a regulatory perspective USP science conference, NJ, September 2004. 2. The effect of pH and homolog length ratio of benzalkonium chloride on its adsorption to a polyene antifungal antibiotic in aqueous suspension Association of Pharmaceutical Scientists (AAPS) conference in Salt Lake City, UT, October 2003. 3. Hemoglobin based oxygen carriers, University of Texas at Arlington, dept. of biomedical engineering, TX, February 2002. 4. Gene Therapies for ocular diseases, Moderator, roundtable at the annual American Association of Pharmaceutical Scientists (AAPS) conference in Denver, CO, October 2001. 5. New and emerging excipients in parenteral medications, University of Arizona, School of Pharmacy, Tucson, AZ, February, 2001 6. Systematic screening of antioxidants for maximum protection against oxidation: An oxygen polarographic study, AAPS, New Orleans, LA, October 1999. 7. Morphology of liposomal dispersions; implications in manufacturability and efficacy, Fine particle conference, Chicago, IL, August 1996. 8. Scale up of liposomal formulations, University of Wisconsin, Madison, WI, August 1996. 9. Encapsulation of insoluble drugs as lipid complexes, University of Iowa, Iowa City, August 1996. 10. Manufacturability of parenteral colloidal dispersions, UMKC, KS, November 1995. 11. Encapsulation of etoposide into liposomes, 10th International symposium on microencapsulation, Austin, TX, September 1995. 12. A new method for determination of surface volume mean diameters of o/w submicron emulsions, AAPS western regional meeting, San Jose, CA, March 1995. 13. Intravenous emulsions, University of Arizona, Tucson, AZ, July 1994. 14. Considerations for sterile filling sub-mL volumes of pharmaceutical solutions South eastern regional AAPS meeting, Durham, NC, April 1994. 15. A phenomenological model for the interfacial configuration of lecithin in parenteral fluorocarbon emulsions Fine particle society meeting, Chicago, IL, August 1993. 16. How is lecithin arranged around fluorocarbon droplets, Vth International symposium on blood substitutes, San Diego, CA, March 1993. 17. A novel method to map size distributions of parenteral fluorocarbon emulsions, PDA annual meeting, Philadelphia, PA, September 1991. 18. Formulation of parenteral fluorocarbon emulsions, Science Expo, Rorer Central Research, Fort Washington, PA, October 1990. 19. Perfluorochemical emulsions as artificial blood, GRASP, 9th annual meeting, Athens, GA, June 1989. Books: 1. S.Apte, R.Sarangarajan. Editors, Cellular respiration and Carcinogenesis, Humana Press. 2009. ISBN: 978-1-934115-07-7 2. S.Apte, S. Ugwu, H.Wang, A.Hawrylechko. Effect of buffers and stabilizers on vaccine stability in Ed. M.Singh, I. Srivastava. Development of vaccines: From discovery to clinical testing, to be published by Wiley, Fourth quarter 2009. .
How to Cite
APTE, Shireesh. Excipient-API interactions in dry powder inhalers. Journal of Excipients and Food Chemicals, [S.l.], v. 3, n. 4, p. 129-142, dec. 2012. ISSN 21502668. Available at: <https://ojs.abo.fi/ojs/index.php/jefc/article/view/177>. Date accessed: 19 feb. 2019.


Dry powder inhaler; lactose; excipient; aerosolization; fine particle fraction; adhesive energy; cohesive energy; lung deposition; inverse gas chromatography; cohesive adhesive balance; particle-particle interactions; Parachor